This numerical study is considered to investigate the erosion in the pipeline systems affected by different parameters such as elbow angle and type, mass flow rate, pipe radius, and wall materials using Computational Fluid Dynamics (CFD). the gravity effect has been considered along the Y-direction. The Standard k-ε model has been selected for turbulence, and standard wall functions have been used for near-wall treatment. Discrete phase modelling (DPM) is selected to model the secondary phase (sand particles). The continuous phase is crude oil, and the discrete phase is sand. The particle characteristics were selected based on the region of Saudi Arabia. Validations are conducted based on the maximum erosion rate at different inlet velocities and particle sizes. Four different elbow angles included 90, 60, 45, and 30 degrees and two types of elbow included sharp and smooth elbow was used to study the behaviour of the erosion rate. The roughness height is selected to introduce the wall material; considering that, each material has a specific roughness height. Therefore, the recognition of every material in this study is done by roughness height. Three parameters of the mass flow rate, tube radius, and roughness height are considered as input parameters to perform the DOE. The DOE study showed that the pipe radius has the most effect on the erosion rate. The reason rate in the Generic models for different angles with curvature(5D) 90°,60°,45°,30°